What to do if I received a summons and complaint from an insurance company for an accident where I did not have insurance?

The complaint is valid because you have been named as the defendant, who was uninsured and at fault in the accident despite the erroneous information about your car.

You will need to file with the court an answer to the complaint and serve a copy by mail on the opposing attorney within the time set forth in the summons.  If you don't timely file an answer to the complaint, the opposing party will obtain a default judgment against you.  A default judgment means you have lost the case.  If that happens, you will need to file a motion to set aside the default.  If the court grants your motion to set aside the default, the case will be back on track and litigation will continue.

The answer to the complaint denies the allegations in the complaint.  You can deny the information in the complaint about your car.

At the law library, look for answer to complaint in the index of Pleading and Practice.  This will give you the general format for an answer to a complaint.  At the end of the answer is the verification which attests to the veracity of the statements in your answer to the complaint.  You sign and date the verification under penalty of perjury.  File with the court the answer to the complaint with verification and an attached proof of service, and serve a copy by mail on the opposing attorney.  You can either use a court form proof of service or you can write your own.  The proof of service verifies the date of mailing to the opposing attorney.  If you write your own proof of service, it just says that you are at least eighteen years of age and the attached documents were sent via first class mail unless stated otherwise to __________ (name and address of opposing attorney) on __________ (date).  You sign and date at the bottom.  The date you sign should be the same as the date of mailing and the same date you file your documents with the court.